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View Full Version : What is important on a Surface Grinder for HSM'er?



Your Old Dog
02-03-2008, 10:46 AM
When I bought my shaper, the guy had a manual surface grinder I could have had real cheap. I passed on it because at the time there was some discussion here on the board about how useless they were if they didn't have automatic feed/power feed. Now I'm thinking, maybe these comments came from some guys who machine for a living and not necessarly Home Shop/Backyard machinist.

I can see some practical applications for one in my shop/tool museum but don't know what might be a good unit to look for given the fact it will only get occasional use. Anyone got any feelings on the matter?

John Stevenson
02-03-2008, 10:58 AM
Mine has power feed, - it's handraulic.

.

bob308
02-03-2008, 11:18 AM
a 6x12 or a 6x18 would be nice. i have done a lot of work on a manual machine. alot of die work and making cutters and punches. they work fine once you get used to it, and will do anything a power feed will do only slower.

mochinist
02-03-2008, 11:28 AM
Mine has power feed, - it's handraulic.

.haha I have one of those too



What Bob said, I would worry a lot less about whether or not it had power feeds and worry about whether or not the grinder is worn out. A worn out grinder is junk unless you are going to learn to scrape, since most work you are doing on a grinder is to <.001" tolerances

Mcgyver
02-03-2008, 11:39 AM
I passed on it because at the time there was some discussion here on the board about how useless they were if they didn't have automatic feed/power feed.

rubbish, if its otherwise a good one and you're hankering for a grinder, run right back and get it . If I was using a grinder all day long and/or if it was a commercial shop and i could be off doing something else while it sparked out, then i can see why power feed would be a requirement. I've found in the home shop it doesn't get used that much - when it does its not like the manual action is a major pita. So once every couple of months i spend half an hour on grinder instead of letting it run on its own - I'm not covering overhead so it isn't an issue.

PS, agree with the other guys, one where the bearings and ways are in good condition would be the most important thing to look for

Your Old Dog
02-03-2008, 11:58 AM
Thanks all. I'm up here in the NE and it's a target rich environment for these kind of things. A 6x18 sounds like it might be a good fit for my shop. Any name brands I could look for? I assume you take your indicators with you when shopping for one of these machines. That means I'll get to demonstrate my ignorance to someone :D

rwf71
02-03-2008, 12:00 PM
I have an all manual old Boyer Schultz 6X12 that I like & use quite a lot. I rarely, ( OK, pretty much never) work to tenths at the jobs I do in my humble home shop but it's good enough for making special paralells that are way more than good enough for the work I do. I use it a lot when it's not really nessasary just cause I like the nice finish I can put on stuff I make. After all it's a hobby for me & if it takes a little extra time to prouduce parts that look better & give me more pride when I show something to a friend it's worth it to me. I gave $400.00 for mine & have never been sorry about the money spent or the space it takes. Just my .02, others may feel differently.
Rick

Your Old Dog
02-03-2008, 12:06 PM
Mine has power feed, - it's handraulic.
John, that handraulic unit ain't the same one you used when you dated Rosey Palm is it? It must be pretty well calloused up by now :D It's a wonder the fingers will still bend!

Rick, sounds like I'll be using mine about the same as you. It may also see some duty as a sharpner for my planer and jointer knives for my woodworking shop.

Spin Doctor
02-03-2008, 12:28 PM
I am looking at this from the prespective if someone that has done Machine Repair and Tool Work for 30+ years. IMO a Surface Grinder is on of the four main machine tools in a shop. The other three are the lathe, mill and band saw. Notice I did not mention a Drill Press. While useful if one has a mill it is already filling that function for the most part. Reasons why a SG is one of the Big Four.

1) If you are making tools to facilitate the machining process (ie Fixtures, Vises, Angle Plates etc) a SG is indispensible to producing quality work.

2) Grinding Form Tools or other specialized cutting tools. With the right fixturing (there's that "F" word again) it is possible to sharpen end mills, counter-bores and the like

3) Surface Finish. Fits and Flatness. The Surface Finish aspect may be a case of "shiny counts" but lets say you were building something with a sliding dovetail like a Boring Head or a Slotting Attachment for the Lathe. This is where Fit comes in While it is possible to fit it with a mill and by a hand a SG makes things a whole heck of a lot easier. Flatness. If you harden anything at all, especially oil or water hardening steels then you know that they "move" when quenched. Getting surfaces back to dead flat is then a matter of either grinding or polishing by hand with a flat surface and 600 grit emery paper. If the surface has to be square or at a specific angle then doing by it hand just got more complicated. Plus normally if you are making a part that is to be hardened it should have excess grinding stock on the critical surfaces. Air Hardening Tool Steels (the A Series) have less of a tendency to move but they still do. Only it is a matter of a magnitude less. For every .010" that O-1 might move A-2 will usually move about .001". Another aspect of Flatness. Spacers and Shims. Lets ay you are rebuilding the spindle on your mill and when you tore it down you found the bearing spacers used to set Pre-Load and Stack Height (the bearing spacers and any lip on the retaining plate/nut must be more than the bore depth, 0.005" is about right) are messed up. And you need to make new ones. If using expensive bearings such as ABEC Class 7s or their ISO equivilants then the spacers have to be flat and parallel. And by flat I don't mean with ih a thou. I mean with in a tenth or less. Perferable less. Plus to set Pre-Loads that are beyond the preload built into the bearing set that height diffrence has to be maintained all across the spacer. You aren't going to get those kind of results in a lathe. I know what I am talking about here. The last four years at my old employer before I retired I rebuilt precision machining spindles. And that meant more than just knocking themapart and throwing a set of bearings in them. That's where the handle I use here and other machining sites comes from.

Your Old Dog
02-03-2008, 01:06 PM
Thanks Spin but lighten up. You just drove the price of every surface grinder up about double with your explanation! I can see we're gonna have a run-to-em. :D

I can see finding one in single phase might be an bit of a problem. Most I've seen are 3phase and I'm leary about going there in my small shop. Is it possible to change out the motor in most of these or is it pretty much impractical to tackle?

Carld
02-03-2008, 01:25 PM
YOD, I bought a Central Machinery surface grinder from a friend at auction and gave $700 for it with a mag base. He used it very little and it's like new. I built a metal stand for it and that sucker is HEAVY, VERY HEAVY, the surface grinder that is. I have found mine does an excellent job and while it is only 6x12 and I would have liked 6x18 it is big enough for me.

If you could find a big name brand cheap and it's not worn out that's better. While the ball type ways are smooth they are also more prone to getting grinding dust in the ways so pull the table off and look at the ways for wear where the balls track.

Unless you are running the grinder for hours every day you don't need power feeds.

lazlo
02-03-2008, 03:36 PM
I am looking at this from the prespective if someone that has done Machine Repair and Tool Work for 30+ years. IMO a Surface Grinder is on of the four main machine tools in a shop.

Good list Spin, but I would argue that a Tool and Cutter Grinder probably has a lot more bang for the buck for the typical HSM than a surface grinder.

With a universal T&C Grinder, you can do the most intricate too grinding jobs, do a much better job on typical toolpost grinding ops, cylindrical grinding, and small (say, 5 x 6") surface grinding jobs.

A good, used surface grinder, with good bearings*, is hard to find in a many places, including Central Texas :)


* Replacing the ABEC-7 bearings in the clapped-out surface grinders you often see "for free" is going to cost several hundred dollars...

pcarpenter
02-03-2008, 06:28 PM
I'd stay away from single phase....and definitely make sure that the grinder has its original motor. Often these are precision balanced unlike your typical machine tool motor. Smooth is everything in a surface grinder and three phase power is less likely to produce some sort of cyclic vibration that shows up in the work.

I've got one of the (newer design) Rockwell-delta toolmaker grinders that is both tool and cutter grinder and surface grinder. It came with a motor that is precision balanced with the pulley in place. Its a three step pulley that uses a flat rubber belt.

If you don't want to build a rotary phase converter (not that hard really) then a VFD is a good option...especially for something like a small surface grinder that likely has a small motor, making for an inexpensive VFD.

Paul

Spin Doctor
02-03-2008, 08:52 PM
Good list Spin, but I would argue that a Tool and Cutter Grinder probably has a lot more bang for the buck for the typical HSM than a surface grinder.

With a universal T&C Grinder, you can do the most intricate too grinding jobs, do a much better job on typical toolpost grinding ops, cylindrical grinding, and small (say, 5 x 6") surface grinding jobs.

A good, used surface grinder, with good bearings*, is hard to find in a many places, including Central Texas :)


* Replacing the ABEC-7 bearings in the clapped-out surface grinders you often see "for free" is going to cost several hundred dollars...

I have to agree that a nice Tool & Cutter Grinder is pretty much a dead even match-up with a Surface Grinder. A T&C will do longer round work than a SG will do in its OD Grinder mode. But it is primarily designed to sharpen cutters. Its OD and Surface modes are something akin to the ShopSmith in its table saw mode. It works but it really doesn't work all that well. For short length OD work a Surface Grinder using a spindex rig of some sort works pretty well out to two or three inches given a hefty enough diameter. If the diameter is too small you can even run into all sorts of problems on a real OD grinder with chatter.

Now the down side of a Surface Grinder (and all grinders in general). They are messy. When dressing the wheel the crap flies all over the place. When grinding the swarf if a fine dust. Even with a dust sucker it can and does make a mess. If you are running coolant it will have certain amount that will get into the air as a fine mist. They can be dangerous. Generally when things go south they go south in a hurry. But then machine tools are no great respecters of human desire to see all of the human body parts staying attached to one another. I still think that it is one of the four most important machines in a machine shop. Be it professional or hobbiest. In addition there are what I think of as the Little Four

1) Cut-Off Saw. Actually a good bandsaw can fulfill alot of this role with the right set up
2) The Pedestal or Bench Grinder. An absolute requirement for grinding lathe tools in HSS. Even if you are finish grinding tools on a SG or T&G the pedestal/Bench Grinder with its coarser wheels will remove metal faster and put less heat into the tool bit.
3) A Belt or Disc Sander. Needed for deburring the ends of stock when they are cut-off. Actually IMO a Disc Sander is the most dangerous tool in the shop especially when working with thin pieces of flat stock. A Pedestal/Bench Grinder with a ScotchBrite Wheel can do a lot of deburring
4) A good quality Bench Vise. We don't think of it as a machine but it is one. The difference between a good one and POS is like night and day.

I am sure others would or do have different opinions. These are mine and I stand by them based on my experience. Other's opinions will be different. That does not mean they are not valid. Just different.

Spin Doctor
02-03-2008, 09:08 PM
Thanks all. I'm up here in the NE and it's a target rich environment for these kind of things. A 6x18 sounds like it might be a good fit for my shop. Any name brands I could look for? I assume you take your indicators with you when shopping for one of these machines. That means I'll get to demonstrate my ignorance to someone :D

Myself I like Harigs. Not the best in the world but for a HSMer light enough to move around (they can go ontop of a bench). The construction is generally simple enough that one with worn ways could be rescraped fairly easily. The motor is part of the spindle itself so it is self contained. When using a indicator on one you are looking for jumps in the reading, not gradual rise or fall fo the indicator.

gary55ford
02-03-2008, 09:33 PM
The one we have at work is a manual machine, but we hooked a Bimba air cyl. to the table & a 2 way valve with a ball actuator on the table stops to change direction, it works great. You still have to manually feed the down travel

darryl
02-03-2008, 11:03 PM
I have no quarrel with anything said above, but the drill press exclusion from the 'main four' doesn't make it with me. I have two drill presses in my home shop, and I use them both everyday. I guess it depends on what you're doing in general, but I couldn't be without one, or using the mill instead. Too much time lost in setup. Heck, I'm finding that I need another lathe just so I don't have to change a setup to make a simple spacer or something.

I could also not be without a table saw in the shop. A lathe project doesn't always require the mill, and a mill project doesn't always require the lathe. But both seem to need the table saw and the bandsaw, and the drum sander. A mill project almost always needs a drill press and the sander, but a table saw project almost never needs the mill or lathe, and not often the sander either.

What my shop really, really needs is a good dust and swarf collector. The kind that goes around finding it and stuffing it into gargabe bags. The machine that does that is usually on strike or something. :)

lane
02-04-2008, 12:07 AM
Mine is Power feed in both axis .But for home shop use a Hand grinder is Plenty but would only want a 6 x12 a 18 is too much to hand crank besides most of your grinding will be under 12" .

DryCreek
02-04-2008, 12:47 AM
A bit of a guess, but suspect the motors are usually three phase because they are inherently smoother than a single phase motor. In grinding, elimination of all vibration, harmonics, etc would be desirable.

Oops sorry, posted before I realized there was a second page.

Your Old Dog
02-04-2008, 07:32 AM
This has been hugely helpful guys, thanks. I like the sound of the Harig, simple and easy to work on is good in this application! I also appreciate the tip of what to look for with the indicator while shopping. My needs are very modest compared to a real machinist, basically I'd like to be able to clean up plate more than actually truing surfaces as nothing I'm doing requires that kind of accuracy (thank God!). I also think a smaller unit will serve my needs better than a large one.

Now to start the search!

David S Newman
02-04-2008, 04:41 PM
I have a Boxford (British) G 200 tool and cutter grinder, which in the manual says it can be used as a small surface grinder with magnetic chuck supplied as an extra. Well mine is single phase had it for many years and it works a treat for surface grinding giving a super finish, it has a table travel of 11-3/8 x 5-1/8 inches, for a small amatuers workshop it can't be faulted . I have all the equipment with it but must admit it's mainly used for surface grinding. These are superbly built machines but are they available in the USA ? David

Roy Andrews
02-05-2008, 02:11 AM
YOD; i dont know where your located in western ny. but im in central square (syracuse area) and make frequent trips to olean, ny. i used to be a union journeyman electrician before the cancer and disability and i have made a few RPC's, so if you get a three phase machine i would be more than willing to come out and help you build and set up a converter. i drink a lot of pepsi though.:cool:

Your Old Dog
02-05-2008, 08:51 AM
That's a generous offer Roy. I'm not far from Rt 77 and fairly close to East Aurora. I have resisted heading in the direction of a converter but realize I'm missing out on a lot of nice equipment opportunities. Let me think on it Roy. I need to figure on a practical HP limit for a one man hobby shop. It would be nice I suppose to have one that would allow me to buy some older 3 hp iron like a old mill or lathe and not have to redo the converter? I'll think on it a bit and I'll get back to you.....with plenty of Pepsi in hand!;)

aboard_epsilon
02-05-2008, 09:29 AM
mines hydraulic ...
there isn't anyway i would have a hand powered one ...not ever.

And I'm only a DIY HSM

sometimes I can be grinding for over an hour and I imagine how many zillion times that machines gone back and forth.......I think, boy, I would definitely NOT like to be doing this by hand .

take my word ..
hydros are out there ...and cheap ......so why bother with hand powered.




all the best.markj

Alistair Hosie
02-05-2008, 09:34 AM
The advice I have been given by expert friends is the same as mark's advice, i.e winding in and out by hand would be terribly laborious after five minutes.Okay I suppose for a quick once over but for serious grinding never.Alistair

Your Old Dog
02-05-2008, 09:44 AM
Aboard and Alistair, well I might not rule one out but if I can find a nice smaller lean 12" type unit I think it would serve my modest means pretty well. Hell, I get a nice finish just using the flycutter and finish is about all I want it for at this point. I don't when I would suddenly develop the skill level to require accuracy as I would get to a tenth on a grinder? LOL I just like the finish they leave on the product.

aboard_epsilon
02-05-2008, 10:42 AM
if you are going to go hand powered ...
you may as well kill two birds with one stone ...
get a tool and cutter grinder ...

typically most have capacity for surface grinding ..

mine shown here ...has functions

surface grinder
tool and cutter grinder
and cylindrical grinder

pic

http://img.photobucket.com/albums/v190/aboard_epsilon/V1.jpg

http://img.photobucket.com/albums/v190/aboard_epsilon/FULL1.jpg


and a link to an old auto one

http://www.youtube.com/watch?v=uexMQNUQGQ4
all the best.markj